luaengine: add emu.romname() method

Signed-off-by: Luca Bruno <lucab@debian.org>
luaengine: add emu.pause()/unpause() methods

Signed-off-by: Luca Bruno <lucab@debian.org>
Merge pull request #64 from lucab/lucab/mame-rr

luaengine: add romname() and pause()/unpause()